Adjustable monitoring guide

ABSTRACT

A roller guide assembly is disclosed for guiding a workpiece into a roll pass of a rolling mill. The guide assembly comprises: a rigid housing structure; a pair of roller holders extending lengthwise of the housing structure on opposite sides of the intended direction of travel of the workpiece; guide rollers rotatably carried on the roller holders, the guide rollers defining a gap therebetween and being configured to engage and guide the workpiece into the roll pass of the rolling mill; pivots for mounting the roller holders on the housing structure for movement about axes extending generally parallel to the rotational axes of the guide rollers; springs for applying forces to the roller holders to rotate the roller holders about their respective axes in directions urging the guide rollers apart; and stops on the housing structure for resisting rotation of the roller holders, at least one of the stops acting through a force sensor to provide a measure of the force being applied to the respective roller holder.

RELATED APPLICATIONS

This application claims priority from Provisional Patent ApplicationSer. No. 60/132,242 filed May 3, 1999.

BACKGROUND

1. Field of the Invention

This invention relates to roller guides of the type employed in rollingmills to guide rod and bar products into roll passes.

2. Description of the Prior Art

In the rolling of steel rods and bars, significant operational benefitscan be realized by employing so-called “reducing-sizing mills” (“RSM”)of the type disclosed in U.S. Pat. No. 5,325,697 issued Jul. 5, 1994 toShore et al., the description of which is herein incorporated byreference in its entirety. Advantages of rolling with such mills includeimproved dimensional control of the finished product, higher millutilization and increased free sizing capability.

FIG. 1 illustrates a typical pass progression of the reducing-sizingprocess, which begins with a leading oval 10 followed by three roundpasses, 12, 14 and 16. Relatively small changes in the finished roundbar or rod can be made by changing the roll partings on the last threeround passes. Alternatively, the feed section, which is typically round,can be changed slightly, but this entails adjusting upstream millequipment, resulting in a non round feed section, which can impose otherprocess limitations.

There has been a reluctance on the part of those skilled in the art toundertake any parting changes to the oval pass 10, owing to problemsassociated with adjusting downstream roller entry guides to exactlymatch the resulting modified oval. Previous technology roller guides donot have the capability to be precisely adjusted whilst located on themill and an offline alignment station is usually used for this, whichobviously requires removal of the guide from the mill and therefore amill stoppage.

Feeding an oversized section through a roller entry guide is notdesirable since this drastically reduces the life of the bearings withinthe guide rollers and can lead to some further processing problems. Ifthe oval section is adjusted to be smaller than the guide setting, asevere oscillation of the rolled product manifests within the guide,causing severe processing problems and poor quality finished product.

An objective of the present invention is to provide a roller guideassembly which can be precisely adjusted on line to accommodatedifferent sized process sections, thus making it possible for example tochange the parting of the oval pass 10, which in turn beneficiallyincreases the free sizing capability of the mill.

Additional objectives and advantages will become evident as thedescription proceeds with reference to the accompanying drawings,wherein:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagrammatic illustration of a typical pass progression in areducing-sizing process;

FIG. 2 is a partially sectioned top plan view of a roller guide assemblyin accordance with the present invention;

FIG. 3 is a partially sectioned side view of the roller guide assembly;

FIG. 4 is a partially sectioned end view of the roller guide assembly asviewed from right to left in FIG. 3;

FIG. 5a diagrammatically illustrates the forces acting on one of theguide arms; and

FIG. 5b is a graph depicting the relationship between the measured forceacting on each roller holder and its deflection from an initialreference setting.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring initially to FIGS. 2-4, a roller guide assembly in accordancewith the present invention is generally indicated at 18. The guideassembly includes a rigid housing structure commonly referred to as a“guide box” having a base 20, with integral laterally spaced sidemembers 22, and a nose piece 24. A pair of roller holders 26 extendslengthwise of the housing structure on opposite sides of the intendeddirection of travel “T” of the workpiece, in this case an oval processsection received from the oval pass 10 for delivery into the nextsuccessive round pass 12.

Guide rollers 28 are rotatably carried at the forward ends of the rollerholders 26. The guide rollers define a gap therebetween, and areconfigured to engage and guide the oval process section so that it iscorrectly presented to the round pass, with the elongate axis “A” of theoval (shown in FIG. 1) normal to the axes of the rolls of the round pass12.

The housing structure further includes vertical pivots 30 on which theroller holders 26 are mounted for movement about axes extendinggenerally parallel to the rotational axes of the guide rollers 28.

Compression springs 32 are located in bores in the roller holders 26.The springs abut the side members 22 of the housing structure and arecaptured in their respective bores by cover plates 34 secured to theroller holders. The springs 32 are loaded in compression and as such,exert yieldable forces “F” (see Figure Sa) on the roller holders urgingthe roller holders to rotate in opposite directions about the pivots 30,as depicted diagrammatically by the arrows in FIG. 2.

The spring-induced rotation of the roller holders is resisted by stopscomprising adjusting screws 36 positioned to be contacted by loadsensitive sensors 38 carried on rearward extensions of the rollerholders.

As can be seen in FIG. 4, the adjusting screws 36 are threaded intoright and left hand threaded sections of the side members 22 of thehousing structure. The square ends 42 of the adjusting screws slideaxially within the square bore 40 of a gear 44 meshing with a gear 46 ona drive shaft 48 having two drive points 48 a, 48 b. The drive point 48a is for manual adjustment, generally used for off-line setting of theguide. The other point 48 b mates with the output shaft 50 of a 90° gearbox 52 powered either manually, or by a motor (not shown) which may becontrolled remotely.

As shown in FIG. 5a, the force F exerted by the spring 32 is opposed byforce “L”, with the sensors 38 serving to measure the magnitude of theforce F.

Various modes of operation are possible after initial set-up.

1. Position Control Mode

FIG. 5b shows that when the guide is adjusted to its desired setting“G₁”, the output of each sensor is recorded as “F₁”. The guide is thendeflected to a different known setting “G₂” by means of gauge bar orother means of controlled deflection (not shown), and the new sensoroutput “F₂” recorded. This can be repeated for several other setting ifdesired for improved accuracy. However, two points are usuallysufficient to describe the relationship between guide setting and sensoroutput which is generally linear.

Knowing the relationship between guide setting and sensor output enablesthe guide to be adjusted to a pre-determined sensor setting “F_(x)”which corresponds to the desired parting between the guide roller“G_(x)”. Hence the guide can be accurately positioned without beingremoved from the mill.

When changes are required to the process oval, the guide can be remotelyadjusted in order to re-position the guide rollers to the desired ovalheight, leading to an increase in the free sizing range capability ofthe reducing and sizing operation.

2. Sensor Output Control Mode

For this mode it is assumed that the spring element used within theguide has negligible variation when the guide parting is adjusted bysmall amounts.

The guide is set as detailed above and once the rollers are at thecorrect setting for the section being rolled, the output of the sensor(or sensors) is recorded.

The guide is then installed on the mill and when the stock enters theguide, the sensor output is again monitored and recorded. If the mill isset correctly, the sensor output during rolling should be very close tothat of the initial setup. If not, then the mill roll gap can beadjusted to change the height of the leading oval until this conditionis met.

When adjustments are required to the oval pass, the guide can beadjusted using the remotely operable adjustment apparatus as detailedabove, such that the parting between the guide rollers is approximatelythe magnitude required by the new set up. When the first bar of the newsize enters the guide, the sensor output is monitored and compared withthe initial setup value. If necessary the guide can be adjustedaccordingly until the correct output is achieved. Ideally this isundertaken in automatic closed loop control, but may also be controlledmanually.

This mode of operation ensures that the guides are always set to matchthe dimensions of the process oval. When the process oval is changed,the guide can be made to adapt accordingly, therefore leading to anincrease in the free sizing range capability of the reducing and sizingoperation.

This mode also enable the guide to be set to eliminate over-loading oroscillating stock as well as enabling the guide to be remotely adjustedin accordance with temperature and yield strength changes associatedwith different grade products.

All of the above concepts can be applied to the rolling of shapes andflat product as well as rounds.

In light of the foregoing, it will now be appreciated by those skilledin the art that various changes and modifications may be made to theembodiment herein chosen for purposes of disclosure without departingfrom the spirit and scope of the invention as defined by the appendedclaims. For example, although compression springs 32 have beendisclosed, other force exerting components could be substituted,including disc springs, fluid actuated devices, elastomers, etc. Thesensors may be other than load sensitive, including for example thosesensitive to strain, pressure deflection, etc. Also, although twosensors are shown, one for each roller holder, an acceptable alternativewould be to employ only one sensor on one of the roller holders.

I claim:
 1. A roller guide assembly for guiding a workpiece into a rollpass of a rolling mill, said guide assembly comprising: a rigid housingstructure; a pair of roller holders extending lengthwise of the housingstructure on opposite sides of the intended direction of travel of theworkpiece; pivot means for mounting said roller holders on said housingstructure for pivotal movement about parallel first axes, said pivotmeans being positioned between forward and rearward sections of saidroller holders; guide rollers carried on the forward sections of saidroller holders for rotation about second axes parallel to said firstaxes, said guide rollers defining a gap therebetween and beingconfigured to engage and guide the workpiece into the roll pass of therolling mill; adjustment means acting on the rearward sections of saidroller holders for pivoting said roller holders in opposite directionsabout said first axes to thereby adjust the size of said gap; forceexerting means for exerting yieldable forces urging the forward sectionsof said roller holders apart while urging the rearward sections of saidroller holders into contact with said adjustment means, the magnitude ofsaid yieldable forces varying in a generally linear relationship withrespect to changes in the size of the gap defined by said guide rollers;and force sensing means associated with said adjustment means forgenerating output signals representative of the magnitude of saidyieldable forces.
 2. The roller guide assembly of claim 1 wherein saidforce sensing means comprises load sensitive sensors interposed betweenboth of said roller holders and said adjustment means.
 3. The rollerguide assembly of claim 1 wherein said force exerting means comprisesresilient springs interposed between said roller holders and adjacentsides of said housing structure.
 4. The roller guide assembly of claim 1wherein said adjustment means is remotely operable.